1. Field
The field of the invention is the safe disposal of medical needles used to withdraw body fluids, and more particularly the disposal of such needles and associated contaminated items.
2. State of the Art
Several manually and electrically powered devices have been proposed for the destruction of used syringe needles. Some destroy only the cannula (needle), shearing it off and depositing it into a receptacle for discard. Others also destruct the plastic hub of the needle and portions of the syringe barrel. See U.S. Pat. Nos. 3,469,750, 4,255,996, 3,851,555 and 4,275,628. All provide receptacles for the severed needles, hubs and other destroyed parts of the syringe. The contaminated syringe bodies must be separately placed in the disposal receptacles when these devices are used, although U.S. Pat. No. 3,469,750 refers to a device which crushes the entire syringe assembly. It is noted that this device is very heavy, stationary and not portable. The large force required is felt to be potentially dangerous.
Blood samples are now generally taken not with syringes for subsequent transfer to a sample container such as a test tube, but directly into such a container. This container is evacuated, sealed by an elastic plug, and placed seal first into an elongate barrel sleeve open at one end and narrowed to a threaded nipple at the other. A double ended tubular sampling needle (cannula) is mounted on a central hub threaded to fit the nipple. The outside end of the cannula is inserted into a vein. The sealed end of the evacuated container is then pressed against the other, inside, end of the needle, puncturing the resilient plug and allowing the internal vacuum to draw the blood sample through the needle into the container. After the needle is withdrawn from the vein, the container is withdrawn from the needle, leaving the sample inside. The sleeve may be safely reused since it never contacts the blood or the body of the patient. However, there is presently no method of removing the needle from the barrel without excessive manipulation and attendant danger of injury and infection to the medical technician. Typically, a needle disposal receptacle is provided with a lid having an aperture shaped to engage the needle hub. See U.S. Pat. No. 4,375,849. The technician, who most often has one hand engaged with the patient's needle wound, must very carefully insert the needle into the narrow opening with the other. Then, he must grip, release and regrip the sleeve several times while rotating it to unscrew it from the needle hub, all with a single hand. It is difficult to perceive when the needle is completely disengaged, and the needle even then tends to hang up in the opening. Danger of injury from the contaminated needles is considerable.
U.S. Pat. Nos. 4,667,821 and 4,738,362 add needle gripping wrenches to the lids, but do not facilitate removal with only one hand. U.S. Pat. Nos. 4,807,344 and 4,862,573 disclose motorized devices permitting one-handed needle removal, but the devices tend to be overly expensive.
The difficulty of disposing of the used needle assembly without manual contact is increased substantially by the configuration of state of the art medical sample needle assemblies. The assemblies have a hub with a flange which is larger in diameter than both the threads and the wrenching or gripping area therebelow. Clearly, state of the art medical sampling needle assemblies with hubs so configured tend to become suspended from any removal tool, whether manually or otherwise powered, rather than falling freely therethrough into the disposal receptacle.
A great need remains for an economical needle removal system allowing facile, safe, one-handed needle removal and disposal.